Wireless multi-site capacity coordination

ABSTRACT

Wireless multi-site capacity coordination includes calculating a total interference impact metric for a reference cell, determining a distribution of power resources for the reference cell and a plurality of neighboring cell is, and allocating the power resources: to sub-bands for the reference cell and the plurality of neighboring cells. Calculating the total interference impact metric may include determining a number of resources assigned to a reference cell within time period T, and calculating user equipment (UE) interference metrics for each UE attached to each of a plurality of neighboring cells which have UE which experiences interference from the reference cell attached.

CROSS-REFERENCES TO RELATED APPLICATIONS

This Application claims priority to U.S. Provisional Application. No.61/619,417 which was filed on Apr. 3, 2012.

BACKGROUND OF THE INVENTION

In a cellular wireless network such as GSM, UMTS, LTE, the number ofuser equipment terminals (UEs) that are attached to each of the cells inthe network can vary substantially. In a conventional network, a UE istypically attached to the cell from which it receives the strongestsignal.

The maximum downlink data throughput that can be achieved by a UEdepends on several factors. For example, the amount of co-channelinterference significantly impacts throughput The amount of interferenceis affected by the transmission power of neighboring cells, the pathloss between the UE and the neighbor cells and the activity level of theneighbor cells.

The total number of active UEs that are being simultaneously served by acell also affects network performance. When a cell serves more and moreUEs, each UE receives a correspondingly smaller share of the fixedamount of wireless resources. In other words, the performance of aparticular cell is inversely proportional to the number of active UEattached to the cell.

Conventional attempts to improve network performance have involvedstatic allocation of various transmission power levels to different-frequency slots, and allocating lower transmission power based on UElocation. However, while static allocation can have a positive effect,it does not adequately account for dynamic elements of the network.

BRIEF SUMMARY OF THE INVENTION

Embodiments of the present invention are directed to methods and systemsfor wireless multisite capacity coordination to facilitate a moreequitable distribution of wireless resources so that the interferenceseen by users on cells serving larger numbers of active user equipmentis decreased, leading to an improvement in performance for those cells.In an embodiment, the interference reduction is achieved by instructingcells serving smaller numbers of user equipment and/or those that causehigher levels of co-channel interference to neighbor cells to reducetransmit power and/or to not transmit at all on certain time and/orfrequency resources.

In an embodiment a system for improving the performance of a wirelesscommunication network, the method includes a processor and anon-transitory computer readable medium with computer executableinstructions stored thereon which, when executed by the processorperforming a method including calculating a total, interference impactmetric for a reference cell, determining a distribution of powerresources for the reference cell and a plurality of neighboring cells,and allocating the power resources to sub-bands for the reference celland the plurality of neighboring cells.

The non-transitory computer readable medium may include additionalinstructions which, when executed by the processor, cause the processorto determine a number of resources assigned to the reference cell withintime period T, and calculate user equipment (UE) interference metricsfor each UE attached to each of a plurality of neighboring cells. Eachof the neighboring cells may have attached UE which experiencesinterference from the reference cell.

In an embodiment; calculating the total interference impact metric forthe reference cell comprises calculating raw interference metrics foreach neighboring cell, determining a total number of active UEs for eachneighboring cell, calculating a total amount of resources used by eachneighboring cell during the time period T, calculating a percentage ofresources used by each neighboring cell during the time period T,calculating an active user multiple for each neighboring cell,multiplying the raw interference metrics for each neighboring cell bythe active user multiple for each neighboring cell to determineindividual interference impact metrics, and summing the individualinterference impact metrics.

Calculating the UE interference metrics may further comprise counting anumber of resources assigned to each neighboring cell during the timeperiod. T, calculating an exponent value from RSSI measurements of thereference cell and each neighboring cell, and calculating UEinterference metrics based on the exponent value. An exponent value fromRSSI measurements may be calculated according to the following equation;

$R_{{Util}{(i)}} = \frac{R_{T{(i)}}}{R_{{Ma}\; x}}$

in which RSSIdB(eNodeB_((i)) represents received signal strengthinformation (RSSI) values received at a UE from the neighboring cell towhich the UE is attached, andRSSIdB(eNodeB_(R)) represents an RSSI value received at a UE from thereference cell. The UE interference metrics may be calculated based onthe exponent value according to the following equation;

UE Interference Metric=(numResources)*e ^(exp) _(—) _(value)

in which. numResources is a number of physical resources used by the UEduring the time period T.

In an embodiment; the percentage of resources R_(Util(i)) used by thei′th neighboring cell is calculated according to the following equation:

$M_{(i)} = {\max \left( {\left( {R_{{Util}{(i)}}*\frac{A_{N{(i)}} - x}{A_{R} + 1}} \right)^{3},0} \right)}$

in which R_(Util(i)) is a total number of wireless resources allocatedto all UEs attached to the neighboring cell i during measurement periodT, and R_(max) is a maximum number of wireless resources than can beallocated to UEs by neighboring cell i during the time period T. Thenon-transitory computer readable medium may include additionalinstructions which, when, executed by the processor, cause the processorto, after calculating the interference impact metric, add eachneighboring cell to a list of neighbor cells for the reference cell. Thelist of neighbor cells may be used to determine the distribution ofpower resources.

In an embodiment, calculating an active user multiple M_((i)) for eachneighboring cell is conducted according to the following equation:

$M_{(i)} = {\max \left( {\left( {R_{{Util}{(i)}}*\frac{A_{N{(i)}} - x}{A_{R} + 1}} \right)^{3},0} \right)}$

in which R_(Util(i)) is the airlink utilization percentage ofneighboring cell s, A_(N(i)) is a number of UE attached to theneighboring cells, A_(R) is a number of active UE attached to thereference cell, and x is a number of active UE which are attached toneighboring cell i,

Various embodiments of the present, invention may be implemented as amethod, a system, or as instructions on a non-volatile computer readablemedium. The scope of the present invention is not limited by theembodiments described herein; rather, the embodiments are provided anddescribed in order to facilitate clear understanding through specificexamples.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a networked computing system according to anembodiment of the present invention.

FIG. 2 illustrates a network topology according to an embodiment of thepresent invention.

FIG. 3 illustrates a network resource controller according to anembodiment of the present invention.

FIG. 4 illustrates a base station according to an embodiment of thepresent invention.

FIG. 5 illustrates user equipment according to an embodiment of thepresent invention.

FIG. 6 illustrates a process for coordinating capacity in a multisitewireless network according to an embodiment of the present invention.

FIG. 7 illustrates a process for collecting data according to anembodiment of the present invention.

FIG. 8 illustrates a process for calculating an interference metricaccording to an embodiment of the present invention,

FIG. 9 illustrates a process for determining power resource allocationaccording to an embodiment of the present invention.

FIG. 10 illustrates variation of transmission power according to-frequency in an embodiment of the present invention.

FIG. 11 illustrates variation of transmission power according to time inan embodiment of the present invention,

FIG. 12 illustrates a process for determining a distribution of powerresources according to an embodiment of the present invention.

FIG. 13 illustrates a process for determining a number of low and highpower sub-bands.

FIG. 14 illustrates a process for coordinated allocation of powerresources according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Embodiments of the present invention may involve a number of hardwareand software components in a wireless network. The invention may beembodied in a networked computer system having a network topology, oneor more Network Resource Controller, a network base station, and aplurality of User Equipment terminals (UEs). The following sectiondescribes these and other hardware and software components according toembodiments of the present invention.

In accordance with an exemplary embodiment of the present invention.FIG. 1 illustrates a networked computing system 100 including variouswired and wireless computing devices that may be utilized to implementany of the wireless multisite capacity coordination processes associatedwith various embodiments of the present invention. These processes mayinclude, but are not limited to network communications statedeterminations such as interference metric determinations, networkresource monitoring, neighboring cell interference rankings, andsub-band transmit power configuration processes.

A networked computing system 100 may include a group of service providercontroller devices 110,112, and 114, any of which may be NetworkResource Controllers (NRCs) or have NRC functionality; network basestations 106 a-e any of which may be NRCs or have NRC functionality,that may share overlapping wireless coverage with one or moreneighboring base stations within a particular region of the networkedcomputing system 100; multiple UE including: cell phone/PDA devices 108a-i, laptop/netbook computers 116 a-b, handheld gaming units 118,electronic book devices or tablet PCs 120, and any other type of commonportable wireless computing device that may be provided with wirelesscommunications service by any of the network base stations 106 a-e; anda data communications network 102 including a backhaul portion that canfacilitate distributed network communications between any of the networkcontroller devices 110, 112, and 114 and any of the network basestations 106 a-e.

As would be understood by those skilled in the Art, in most digitalcommunications networks, the backhaul portion of a data communicationsnetwork 102 may include intermediate links between a backbone of thenetwork which are generally wireline, and sub networks or network basestations 106 a-e located at the periphery of the network. For example,cellular user equipment (e.g., any of user equipment 108 a-i, 116 a-b,118, and 120) communicating with one or more network base stations 106a-e may constitute a local sub network. The network connection betweenany of the network base stations 106 a-e and the rest of the world mayinitiate with a link to the backhaul portion of an access provider'scommunications network 102 (e.g., via a point of presence).

A Network Resource Controller (NRC) is a physical entity that mayinclude software components. An NRC may facilitate all or part of thewireless multisite capacity coordination processes associated withvarious embodiments of the present invention, in accordance with anembodiment of the present invention, an NRC that performs a particularwireless multisite capacity coordination process may be a physicaldevice, such as a network controller device 110,112, and 114 or anetwork base station 106 a-e. In yet another embodiment, an NRC thatperforms a particular wireless multisite capacity coordination processmay be a logical software-based entity that can be stored in thevolatile or non-volatile memory or memories, or more generally in anon-transitory computer readable medium, of a physical device such as anetwork controller device 110,112, and 114, or a network base station106 a-e.

In accordance with various embodiments of the present invention, the NRChas presence and functionality that may be defined by the processes itis capable of carrying out. Accordingly, the conceptual entity that isthe NRC may be generally defined by its role in performing processesassociated with various wireless multisite capacity coordinationprocesses. Therefore, depending on the particular embodiment, the NRCentity may be considered to be either a physical device, and/or asoftware component that is stored in the computer readable media such asvolatile or non-volatile memories of one or more communicating device(s)within a networked computing system 100.

In an embodiment, any of the service provider controller devices110,112, and 114, and/or network base stations 106 a-e (optionallyhaving NRC functionality or considered to be a NRC) may functionindependently or collaboratively to implement any of the interferencemitigation processes associated with various embodiments of the presentinvention. Further, any of the interference mitigation processes may becarried out via any common communications technology known in the Art,such as those associated with modern Global Systems for Mobile (GSM),Universal Mobile Telecommunications System (UMTS), Long Term Evolution(LTE) network infrastructures, etc.

In accordance with a standard GSM network, any of the service providercontroller devices 110, 112, and 114 (NRC devices or other devicesoptionally having NRC functionality) may be associated with abasestation, controller (BSC), a mobile switching center (MSG), or any othercommon, service provider control device known in the art, such as aradio resource manager (RRM). In accordance with a standard UMTSnetwork, any of the service provider controller devices 110,112, and 114(optionally having NRC functionality) may be associated with a networkresource controller (NRC), a serving GPRS support node (SGSN), or anyother common service provider controller device known in the art, suchas a radio resource manager (RRM). In accordance with a standard LTEnetwork, any of the service provider controller devices 110, 112, and114 (optionally having NRC functionality) may be associated with aneNodeB base station, a mobility management entity (MME), or any othercommon service provider controller device known in the art, such as anRRM.

In an embodiment, any of the service provider controller devices110,112, and 114, the network base stations 106 a-e, as well as any ofthe user equipment 108 a-i, 116 a-b, 118, and 120 may be configured torun any well-known operating system, including, but not limited to:Microsoft® Windows®, Mac OS®, Google® Chrome®, Linux®, Unix®, or anymobile operating system, including Symbian®, Palm®, Windows Mobile®,Google® Android®, Mobile Linux®, etc. In an embodiment, any of theservice provider controller devices 110,112, and 114, or any of thenetwork base stations 106 a-e may employ any number of common server,desktop, laptop, and personal computing devices.

In an embodiment, any of the user equipment 108 a-i, 116 a-b, 118, and120 may be associated with any combination of common mobile computingdevices (e.g., laptop computers, netbook computers, tablet computers,cellular phones, PDAs, handheld gaming units, electronic book devices,personal music players, MiFi™ devices, video recorders, etc.), havingwireless communications capabilities employing any common wireless datacommunications technology, including, but not limited to: GSM, UMTS,3GPP LTE, LTE Advanced, WiMAX, etc.

In an embodiment, the backhaul portion of the data communicationsnetwork 102 of FIG. 1 may employ any of the following commoncommunications technologies; optical fiber, coaxial cable, twisted paircable, Ethernet cable, and powerline cable, along with any otherwireless communication technology known in the art. In an embodiment,any of the service provider controller devices 110,112, and 114, thenetwork base stations 106 a-e, and user equipment 108 a-i, 116 a-b, 118,and 120 may include any standard computing software and hardwarenecessary for processing, storing, and communicating data between eachother within the networked computing system 100. The computing hardwarerealized by any of the network computing system 100 devices (e.g., anyof devices 106 a-e, 108 a-i, 110, 112,114, 116 a-b, 118, and 120) mayinclude; one or more processors, volatile and non-volatile memories,user interfaces, transcoders, modems, wireline and/or wirelesscommunications transceivers, etc.

Further, any of the networked computing system 100 devices (e.g., any ofdevices 106 a-e, 108 a-i, 110, 112, 114, 116 a-b, 118, and 120) mayinclude one or more computer readable media encoded with a set ofcomputer readable instructions, which when executed, can perform aportion of any of the wireless multisite capacity coordination processesassociated with various embodiments of the present invention. In contextwith various embodiments of the present invention, it should beunderstood that wireless communications coverage associated with variousdata communication technologies (e.g., network base stations 106 a-e)typically vary between different service provider networks based on thetype of network and the system infrastructure deployed within aparticular region of a network (e.g., differences between GSM, UMTS,LTE, LIE Advanced, and WiMAX based networks and the technologiesdeployed in each network type).

FIG. 2 illustrates a network topology 200 including various network basestations 204 a, 206 a, and 208 a having overlapping coverage areas 204b, 206 b, and 208 b that maybe part of a larger data communicationsnetwork (e.g., 100 of FIG. 1), as well as various user equipment 210a-f, 212 a-e, 214 a-c, and 216 a-b that may be geographically locatedwithin the respective coverage areas 204 b, 206 b, and 208 b of any ofnetwork base stations 204 a, 206 a, and 208 a. The network base stations204 a, 206 a, and 208 a and user equipment 210 a-f, 212 a-e, 214 a-c,and 216 a-b depicted in FIG. 2 may be representative of any of thenetwork base stations 106 a-e or user equipment 108 a-i, 116 a-b, 118,and 120 depicted in FIG. 1.

In an embodiment, the network topology 200 may be consistent with anycommon LTE, LTE Advanced, GSM, UMTS, and/or WiWAX based networktopology, etc. In particular, the network, topology 200 depictsoverlapping cell coverage areas amongst various network cells (e.g.,homogeneous or heterogeneous mixtures of network cells) and various userequipment 210 a-f, 212 a-e, 214 a-c, and 216 a-b that maybeindependently and dynamically distributed within the coverage areas 204b, 206 b, and 208 b of multiple network base stations 204 a, 206 a, and208 a. In an embodiment, user equipment 210 a-f are geographicallypositioned within the cell coverage area 204 b of network base station204 a, and accordingly, user equipment 210 a-f may only experience lowlevels of intercell, co-channel interference from either base station206 a or 208 a. Similarly, user equipment 212 a-e are geographicallylocated solely within the cell coverage area 208 b of network basestation 208 a, and accordingly, user equipment 212 a-e may onlyexperience low levels of intercell, co channel interference from eitherbase station 204 a or 206 a. User equipment 216 a-b are geographicallypositioned solely within the cell coverage area 206 b of network basestation 206 a, and accordingly, user equipment 216 a-b may onlyexperience low levels of intercell co-channel interference from eitherbase station 204 a or 208 a.

In contrast, user equipment 214 a-c are geographically positioned withinoverlapping cell coverage areas 204 b, 206 b, and 208 b of network basestations 204 a, 206 a, and 208 a. Although user equipment 214 a-c may beselectively serviced by one base station such as base station 206 a,user equipment 214 a-c may also experience substantial intercellco-channel interference from neighboring base stations 204 a and 208 a,As would be understood by those skilled in the Art, in most real worldscenarios, substantial levels of intercell co-channel interferencegenerally occur at the periphery of most cells that are bordered by orsharing a geographic coverage area with one or more neighboring cells.Accordingly, it should be understood that the network topologyillustratively depicted in FIG. 2 is only being utilized to depictsimplified concepts associated with intercell co-channel interference.

In the scenario of FIG. 2, various service provider controller devices110, 112, and 114 and/or any of network base stations 204 a, 206 a, and208 a, as well as any of the distributed user equipment 210 a-f, 212a-e, 214 a-c, and 216 a-b, may be configured to perform a portion of thewireless multisite capacity coordination processes. In an embodiment,network communications state determinations may use any of the userequipment experiencing co-channel interference to measure and/ordetermine various interference metrics (e.g., carrier power from aserving base station, noise power, interference powers from neighboringbase stations, carrier to interference-plus-noise ratio (CINR), etc.) inorder to facilitate further wireless multisite capacity coordinationoperations. In an embodiment, any of the network base stations 204 a,206 a, and 208 a may carry out various multisite capacity coordinationdeterminations based on feedback from user equipment which generallywill include interference metric measurement data (e.g., carrier powerfrom, a serving base station, noise power, interference powers fromneighboring base stations, etc). These determinations may facilitatefurther wireless multisite capacity coordination operations to becarried out by a NRC entity.

In an embodiment, neighboring cell negotiations and determinationsrelating to various wireless multisite capacity coordination processesmay require any pair or group of network base stations 204 a, 206 a, and208 a (any of which may be acting as an NRC or possess NRCfunctionality), having overlapping coverage, to communicate with eachother in order to facilitate autonomous and/or collective determinationsassociated with each network base station's 204 a, 206 a, and 208 apreferred, coordinated downlink sub-band transmit power configurations.In other embodiments, neighboring cell negotiations relating to variouswireless multisite capacity coordination processes may also occur at aseparate NRC entity (not shown) that may be, for example, one or more ofservice provider controller devices 110, 112, and 114 (optionally actingas NRCs or possessing NRC functionality). In these embodiments the NRCmay acquire various metrics from distributed user equipment 214 a-cfeedback (e.g., carrier power from a serving base station, noise power,interference powers from neighboring base stations, CINR, etc). Based onthis feedback, and the results of processes implemented at various basestations, discussed further herein, the controlling NRC may be able tomake determinations associated with each network base station's 204 a,206 a, and 208 a preferred, coordinated downlink sub-band transmit powerconfigurations. The preferred, downlink sub-band transmit powerconfigurations for the base stations 204 a, 206 a, and 208 a aregenerally configured to equitably distribute capacity across basestations with varying numbers of user equipment by reducing the amountof wireless resources available to base stations providing service tolower numbers of user equipment while maximizing the amount of wirelessresources available to base stations providing service to larger numbersof user equipment.

FIG. 3 illustrates a block diagram view of an NRC 300 that may berepresentative of any of the network base stations 106 a-e or any of thenetwork controller devices 110,112, and 114 depicted in FIG. 1. Inaccordance with an embodiment of the present invention, the NRC 300 maybe associated with any common base station or network controller deviceknown in the Art, such as an LTE eNodeB (optionally comprising awireless modem), RRM, MME, RNC, SGSN, BSC, MSC, etc. The NRC 300 mayinclude one or more data processing device including a centralprocessing unit (CPU) 302. In an embodiment, the CPU 302 may include anarithmetic logic unit (ALU, not shown) that performs arithmetic andlogical operations and one or more control units (CUs, not shown) thatextract instructions and stored content from memory and then executeand/or processes them, calling on the ALU when necessary during programexecution. The CPU 302 may be responsible for executing all computerprograms stored on the NRC's 300 volatile (RAM) and non-volatile (e.g.,ROM) system memories 306 and storage 308. Storage 308 may comprisevolatile or non-volatile memory such as RAM, ROM, a solid state drive(SSD), SDRAM, or other optical, magnetic, or semiconductor memory.

The NRC 300 may also include a network interface/optional user interfacecomponent 304 that can facilitate the NRC's 300 communication with thebackhaul 102 portion or the wireless portions of the network computingsystem 100 of FIG. 1, and may facilitate a user or network administratoraccessing the NRC's 300 hardware and/or software resources. A storage308 includes a network resource monitor component 310 that can monitor apresent state of dynamically changing network environments and thecorresponding effect of these changes on various network resources(e.g., on user equipment, communications quality and networkthroughput)., and a network resource transmit power configurationcomponent 312 that can determine downlink sub-band transmit power levelsfor one or more neighboring network, base stations (e.g., any of networkbase stations 106 a-e). Storage 308 may further include interferencerankings 314 for neighboring network base stations and/or the UEs thatthey service. The interference rankings 314 may include signal strengthand/or interference level data, such as the interference impact of onebase station's communications on one or more UE serviced by aneighboring base station. The interference rankings 314 may be updatedperiodically using information received from, for example, UE, basestations, and service provider controller devices 110,112, and 114. Eachof the components of FIG. 7 maybe coupled to a system bus 318 thatfacilitates data communications between all the hardware resources ofthe NRC 300.

FIG. 4 illustrates a block diagram view showing components of a networkbase station 400 according to embodiments of the present invention. Thenetwork base station 400 includes components that maybe included in anyof network base stations 106 a-e, 204 a, 206 a, or 208 a, shown in FIG.1 or FIG. 2.

The network base station 400 may include one or more data processingdevices including a central processing unit (CPU) 402. In an embodiment,the CPU 402 may include an arithmetic logic unit (ALU, not shown) thatperforms arithmetic and logical operations and one or more control units(CUs, not shown) that extract instructions and stored content frommemory and then executes and/or processes them, calling on the ALU whennecessary during program execution. The CPU 402 may execute computerprograms stored on the network base station's 400 volatile (RAM) andnon-volatile (e.g., ROM) system memories 406, or in storage 408. Storage408 may comprise volatile or non-volatile memory such as RAM, ROM, asolid state drive (SSD), SDRAM, or other optical, magnetic, orsemiconductor memory.

The network base station 400 may also include a network interfacecomponent 404 that facilitates the network base station's 400communication with the backhaul 102 portion or the wireless portions ofthe network computing system 100 of FIG. 1; a modem 418 for modulatingan analog carrier signal to encode digital information and fordemodulating a carrier signal to decode digital information; a wirelesstransceiver component 420 for transmitting and receiving wirelesscommunications to and from devices in wireless communication with thenetworked base station 400, such as any of the wireless enabledcomputing devices (e.g., any of the network base stations 106 a-e, oruser equipment 108 a-i, 116 a-h, 118, and 120 of FIG. 1) of thenetworked computing system 100; a system bus 422 that facilitates datacommunications between the hardware resources of the network basestation 400; and storage 408, which may include one or more of: anetwork resource manager component 410, a network resource controller412, an interference metric preprocessor 414, and a repository ofneighboring base station profiles 41.6.

In accordance with an embodiment of the present invention, the networkresource manager component 410 may be configured to communicate andcollaborate with one or more of service provider controller devices110,112, and 114, and/or neighboring base stations 106 a-e, to affectvarious capacity coordination decisions related to interference. In suchan embodiment, the network base station 400, one or more neighboringnetwork base stations, and any of the sen-ice provider controllerdevices 110, 112, and 114 may be acting independently or collectively asa NRC device. In an embodiment, the base station 400 may include an NRCcomponent 412 as a software component of storage 408. The NRC component412 may include one or more of the components disclosed with respect tostorage 308, including network resource transmit power configurationcomponent 312, network resource monitor 310, and interference rankings314.

In an embodiment where the NRC 300 is a separate entity, theinterference metric preprocessor 414 may be capable of performingvarious wireless multisite capacity coordination processes associatedwith a NRC 300, in such an embodiment the base station 400 may becapable of performing a portion of the data processing explained withrespect to NRC 300 in order to reduce the amount of data flowing betweenthe base station and a separate NRC 300. In other words, in anembodiment, functions of NRC 300 may be shared between preprocessor 414and a separate NRC unit.

Processes that may be executed by preprocessor 414 include processing atleast one of carrier power, reference signal, power, and pilot signal,power from the serving base station 400, processing at least one ofnoise power, carrier powers, reference signal power, and pilot signalpowers from neighboring base stations, calculating CINR, etc. Forexample the interference metric preprocessor 414 may generate histogramsassociated with signal strength measurements based on received signalstrength measurements (e.g., measured/determined signal strength metricdata from its serviced user equipment). This front end processinggenerally results in less data needing to be sent to a central NRC 300,when the NRC 300 is a separate entity from the base station 400. In suchan embodiment, communications bandwidth and centralized NRC 300processing resources can be conserved by distributing certain tasks tocapable network base station 400 resources. In an embodiment, the NRC300 may request information from the network base station 400, includingany new or updated information relating to its own available resources,communications quality states, or the current interference levels causedby neighboring network base stations. Alternatively, the network basestation 400 may autonomously provide the NRC 300 with new or updatedinformation it detects or determines on a periodic basis.

In an embodiment, the network base station transceiver 420 may use anycommon modulation/encoding scheme known in the art, including, but notlimited to Binary Phase Shift Keying, Quadrature Phase Shift Keying, andQuadrature Amplitude Modulation. Additionally, the network base station400 may be configured to communicate with the user equipment (e.g., anyof devices 108 a-i, 116 a-b, 118, and 120) via any Cellular DataCommunications Protocol including any common LTE, LTE-Advanced, GSM,UMTS, or WiMAX protocol.

FIG. 5 illustrates a block diagram view of user equipment CUE) 500 winchmay be in wireless communication with a base station. User equipment 500may be any of user equipment 108 a-i, 116 a-b, 118, 120, 210 a-e, 212a-e, 214 a-c, or 216 a-b depicted FIGS. 5 and 6.

In accordance with an embodiment of the present invention, the userequipment 500 may include one or more data processing device such ascentral processing unit (CPU) 502. In an embodiment, the CPU 502 mayinclude an arithmetic logic unit (ALU, not shown) that performsarithmetic and logical operations and one or more control units (CUs,not shown) that extract instructions and stored content from memory andthen executes and/or processes them, calling on the ALU when necessaryduring program execution. The CPU 502 may be responsible for executingall computer programs stored on the user equipment's 500 volatile (RAM)and non-volatile (e.g., ROM) system memories, 506 and 508.

The user equipment 500 may also include: a network interface component504 that can facilitate communication between user equipment 500 andlocally connected computing devices (e.g., a Personal Computer); a modem516 for modulating an analog carrier signal to encode digitalinformation and for demodulating a carrier signal to decode digitalinformation; a wireless transceiver component 518 for transmitting andreceiving wireless communications to and from any of the wirelessenabled computing devices (e.g., any of the network base stations 106a-e of FIG. 1) of the networked computing system 100; a system bus 520that facilitates data communications between hardware resources of theuser equipment 500; an optional display unit 522 to display text orgraphics information; an optional user input device 524 such as akeyboard, mouse, or touch-screen; and a storage 508 which may include: asignal strength measurement unit 510, an operating system/applicationsrepository 512, and a data, repository 514 storing various userequipment data.

In an embodiment., the signal strength measurement unit 510 is capableof measuring various communications information associated withinterference metric data, such as carrier power, reference signal power,pilot signal power, etc. from a serving base station, noise power,interference powers (e.g., carrier power, reference signal power orpilot signal power, etc) from neighboring base stations, etc. Further,the signal strength measurement unit 510 may also be capable ofcalculating CINR data based on the measured interference metric datacited above. The measured signal strength metric data and the optionalcalculated CINR data may be collectively referred to herein as eithersignal strength measurement data and/or interference metric data.

In various embodiments, CINR calculations, including calculations basedon measurements of base station and interfering base station signalstrength, may occur at a network base station 400, a separate NRC 300,NRC components within a base station 400, or a combination of devices.The signal strength measurement unit 510 may be capable of calculatingboth an aggregate CINR (ratio of the carrier power to the sum of theinterference powers from all interfering base stations) and anindividual interfering base station CINR (ratio of the carrier power tothe interference power of a single base station).

The data repository 514 may be utilized by the user equipment 500 tostore various signal strength metric data, including determined CINRdata. In an embodiment, this data may be periodically transmitted to aNRC entity or a base station having NRC functionality. Alternately, theNRC may periodically request and acquire the interference metric datafrom the user equipment 500.

In a cellular wireless network using a standard such as GSM, UMTS, LTE,and the like, the number of UEs that are attached to each of the basestations in the network can vary substantially,. A network topology mayinclude a plurality of base stations, each of which may be attached to adifferent number of UEs.

In a wireless network, the number of UEs attached to a particular basestation is a function of the number of active users in the basestation's coverage area. If a large number of users are closer to aparticular base station than its neighbors, the particular base stationmay have a larger number of UEs attached, to it than its neighbors do,even though some of the UEs are within service range of the neighboringbase stations. For example, with reference to elements of FIG. 2, basestation 206 a has less active attached UE than neighboring base stations204 a and 208 a, and UE 214 a-c are receiving interference from allthree base stations,

In a simplified example, UE 214 c and 214 b, which are attached to basestations 204 a and. 208 a, respectively, are receiving interference frombase station 206 a. Reducing resources used by base station 206 a willreduce the interference experienced by UE 214 b-c. Although the totalresources available to base station 206 a is reduced, base station 206 ais serving fewer UEs, so even with a reduced number of resources, theseUEs may still see above average levels of performance. A process forcoordinating a plurality of base stations to efficiently allocateresources maybe referred to as wireless multisite capacitycoordination,.

An embodiment of a process 600 for wireless multisite capacitycoordination is shown in FIG. 6. As seen in FIG. 6, wireless multisitecapacity coordination process 600 may include collecting data 602,calculating an interference metric 604, determining power resourceallocation 606, and allocating resources 608. Each of these items willbe explained in the following description.

Steps that may be taken in a process 700 of collecting data will now bedescribed with respect to FIG. 7. As seen in the figure, a process 700of collecting data may include a step 702 of collecting signal strengthinformation. In an embodiment, the signal strength information is pilotsignal received signal strength indication (RSSI) information. A pilotsignal RSSI value may be calculated by a UE that is attached to a basestation, and may be calculated according to various techniques known inthe art,

Each base station may serve a number of carriers operating on differentrespective frequencies, and includes a number of antennae which eachhave a physical coverage area. As used herein, the term “cell” refers toan area served by a single antenna for a given carrier frequency. Thecoverage area of a cell may relate to the signal strength of aparticular carrier signal, such that the boundaries of the cell aredefined by points at which the signal strength drops crosses a thresholdvalue, or by points at which the interference rises above a thresholdvalue. Each cell is served by a given base station, so when UE isdescribed as being attached to a cell, it is also attached to theparticular base station associated with the cell in addition, activitiesthat are described as being conducted by a cell may be conducted by thebase station that is associated with the particular cell. A single basestation may serve a plurality of cells, each of which has a separate,and possibly overlapping, coverage area,

In an embodiment, a pilot RSSI value is the signal strength in dB of thepilot channel, transmissions that a UE receives from a cell, in LTEsystems, for example, this can be the Reference Signal Receive Power(RSRP) measured by the UE for that cell. In UMTS networks this can bethe Common Pilot Channel Received Signal Code Power (CPICH RSCP). TheRSSI measurement may be independent of whether or not downlink trafficis being transmitted for that cell.

A UE may determine an RSSI value for every cell whose coverage areaoverlaps with the UE location. A UE may be within a cell if a receivedsignal exceeds a threshold value. Thus, if a UE is in the coverage areaof six cells, the UE may calculate a pilot RSSI value for each of thesix cells.

The pilot. RSSI value may be expressed in several forms, including a rawdecibel value, a number on an arbitrary scale, or another form thatreflects magnitude of signal strength. The pilot RSSI value may bedetermined by the UE and transmitted to a base station to which it isattached, or is otherwise in communication, with the UE. The pilot RSSIvalue is then received by the network resource controller 300 that maycalculate an interference metric in a subsequent operation.

In step 704, the NRC 300 that calculates the interference metricdetermines a number of active UE for a cell. The number of active UEsfor a cell may be distinct from the number of UEs that are attached tothe cell. A UE may be attached to a cell but not engaged in activecommunication with the cell. In general, the number of active UE is lessthan or equal to the total number of UE that are attached to a cell. Thenumber of active UE attached to a neighboring cell, eNodeB_(C(i)), maybe referred to as A_(N(i)), while the number of UE attached to areference cell, eNodeB_(R) may be referred to as A_(R).

In an embodiment, a UE is considered to be an active UE based on anamount of wireless resources consumed by the UE in a predetermined timeperiod T. More specifically, the number of active UEs may be the numberof UEs that consume more than a threshold portion ACT_(MIN) of a cell'sresources within a measurement, period T. For example, the number ofactive UEs may be the number of UEs that consume more than 1% of acell's resources (ACT_(MIN)=1%) within a 250 millisecond interval.(T=250 ms). although, embodiments of the present invention are notlimited to these specific examples. Wireless resources can be time,frequency, and power. In LTE, time and frequency resources are known asa resource block. In UMTS, resources can be time and/or power.

In other embodiments, values for measurement period T may be fromseveral milliseconds to several seconds, or longer. Examples of valuesof T include 10, 25, 100, or 500 milliseconds, one second, five seconds,and one minute. The percentage ACT_(MIN) may refer to a percentage ofthe total available (maximum) resources that are used. The percentagevalue may differ across various embodiments.

The number of active UEs for a cell can be referred to as an activitymetric, and the activity metric may include more than one time period T.For example, the activity metric may be determined for the most recent2, 5, 10, or 100 time periods.

In step 706, the NRC 300 that calculates the interference metriccollects RSSI information from UE. NRC 300 may collect RSSI data for allactive UE attached to each cell 106 in a networked computing system 100.

FIG. 8 illustrates a process 800 of calculating interference impactmetrics for a reference cell according to an embodiment of the presentinvention. The interference metrics may be calculated by an NRC 300,components of which may be located at one or more base stations 106 orat a remote location. A total interference impact metric is ultimatelycalculated with respect to a reference cell, which is expressed in thefollowing sections as eNodeB.

A total interference impact metric provides an indication of the amountof interference that a given cell is causing to the UEs attached toneighboring cells. The total interference metric may take into accountone or more of the following factors: 1) interference caused by areference cell to active UEs attached to neighboring cells, 2) theamount of wireless resource utilization of neighboring cells, and 3) thenumber of active UEs being served by neighboring cells.

Furthermore, a total interference impact metric may have one or more ofthe following characteristics. First, a larger amount of interferenceseen by UEs being served by neighboring cells from the given cell maylead to a larger total interference impact metric. Second, a largerwireless resource utilization percentage of neighboring cells may leadto a larger total, interference impact metric. And third, the magnitudeof the total interference impact metric for a particular cell mayincrease with an increase in the number of active UEs that cell iscausing interference to.

Embodiments of the present invention may calculate a UE interferencemetric for each neighboring cell of a reference cell, eNodeB_(R). Aneighboring cell, which is expressed as eNodeB_(C(i)), is a cell thathas UEs attached to it which experience interference from reference celleNodeB_(R). The “C” notation comes from the view that the neighboringcells form a cluster with reference cell eNodeB_(R). If there are Nneighboring cells, the index 1 ranges from 1 to N. Each reference celland its neighboring cells may be considered as part of a single cluster.The neighboring cells for a reference cell may change over time, forexample by the movement of UE.

Although the term eNodeB is associated with the LTE standard, it shouldbe understood that embodiments of the present invention are not limitedto LTE. In other embodiments, the reference cell may be a cellulartransceiver that is individually managed to send and receivetransmissions to a plurality of UE within its coverage area.

In step 802, the number of resources assigned to eNode_(C(i)) to aparticular UE (UE_(i)) during the last measurement period T isdetermined. In the following equations, the value determined throughstep 802 is expressed as numResources. In LTE systems, for example,numResources may be the number of physical resource blocks (PRBs) thatwere used during the last measurement period T. In UMTS, numResourcesmay be the sum of the linear transmit powers of the signals sent in eachtransmit time interval (TTI).

In step 804, an exponent value is calculated using the RSSI valuescollected in step 702. In an embodiment, the exponent value is expressedby the following equation 1,

$\begin{matrix}{{exp\_ value} = \frac{12.0 - \left( {{{RSSIdB}\left( {eNodeB}_{c{(i)}} \right)} - {{RSSIdB}\left( {eNodeB}_{R} \right)}} \right.}{3.0}} & \left\lbrack {{Equation}\mspace{14mu} 1} \right\rbrack\end{matrix}$

in which RSSIdB is the RSSI value between UE_(i) and the relevant cellexpressed in a decibel scale.

In step 806, a UE interference metric is calculated. The UE interferencemetric is calculated as a function of the difference between the signalstrength seen by the UE from its serving cell, eNodeB_(C(i)) and theinterference received from the reference cell, eNodeB_(R). The smallerthe difference in signal strength between the serving cell.eNodeB_(C(i)) and the interfering cell eNodeB_(R), the larger theinterference metric should be. In an embodiment, the interference metricincreases exponentially as the difference in RSSI values decreases. Whenthe UE interference metric increases exponentially, substantialperformance gains may be achieved compared to having the UE interferencemetric increase linearly.

Accordingly, in an embodiment, the UE interference metric may bedetermined according to the following equation 2, using variables thathave been defined above:

UE Interference Metric×(numResources)*e^(exp) _(—) _(value)   [Equation2]

FIG. 9 illustrates the relationship between the UE interference metricand the difference in RSSI values between a neighboring cell and areference cell calculated according to equation 2.

In step 808, a raw interference metric I_(raw(i)) is calculated for eachneighboring cell, where i denotes the particular cell 1 to N. The rawinterference metric may be calculated by adding the UE interferencemetric for every active UE attached to neighboring cells eNodeB_(C(i)).Thus, raw interference metric I_(raw(i)) may be calculated for everyneighboring cell.

In step 810, a total number of active UE which are attached to eachneighboring cell eNodeB_(C(i)) is determined. In an embodiment, thisnumber is referred to as A_(N(i)), and obtaining the number is describedabove with respect to step 704. Next, in step 812, a total number ofresources used R_(Ti(i)) is determined for each neighbor node. The totalnumber of resources used may be the total resources used by eachneighboring cell eNodeB_(C(i)) during measurement period T.

In step 814, a wireless resource utilization percentage R_(Util(i)) iscalculated for each, neighboring cell, eNodeB_(C(i)). In an embodiment,the wireless resource utilization percentage R_(Util(i)) is expressed bythe following equation 3.

$\begin{matrix}{R_{{Util}{(i)}} = \frac{R_{T{(i)}}}{R_{Max}}} & \left\lbrack {{Equation}\mspace{14mu} 3} \right\rbrack\end{matrix}$

in which R_(max) is the maximum number of wireless resources than can beallocated to UEs by a cell during measurement period of duration T. Fora constant measurement period T, the value for R_(max) may be constant.A wireless resource utilization percentage may be determined separatelyby each base station, or by a separate network; resource controllercomponent.

In step 816, an active user multiple M_(i) is calculated for eachneighboring cell eNodeB_(C(i)). In an embodiment, the active usermultiple is calculated according to the following equation 4.

$\begin{matrix}{M_{(i)} = {\max \left( {\left( {R_{{Util}{(i)}}*\frac{A_{N{(i)}} - x}{A_{R} + 1}} \right)^{3},0} \right)}} & \left\lbrack {{Equation}\mspace{14mu} 4} \right\rbrack\end{matrix}$

in which Ar refers to the number of active UE attached to reference celleNodeB_(R) as described with respect to step 704. A_(R) is the number ofUEs which exceed threshold ACT_(MIN) during the most recent measurementperiod for that eNodeB. The total number of Active UEs attached toneighbor cell eNodeB_(C(i)) that is serving UEs receiving interferencefrom eNodeB_(R), is denoted by A_(N(i)). In other words, A_(N(i)) is thetotal number of UEs on eNodeB_(C(i)) which exceed threshold ACT_(MIN)during the most recent measurement period for that cell, x is a numberof active UEs attached to the neighbor cell, such that if there are x orfewer active UEs on the neighbor cell, then the active user multiple forthat neighbor cell will be zero.

The active user multiple formula adjusts the raw interference metric toaccount for the ratio of active UEs on the reference cell eNodeB_(R) andthe neighbor cell eNodeB_(C(i)), and the utilization percentage of theneighboring cell. In an embodiment, when the ratio of UEs between aneighboring cell and reference cell increases, for example by addingmore users to the neighboring cell than the reference cell, the usermultiple also increases.

In an embodiment, if there are fewer than a certain number of UEsreceiving service from the neighboring cell, the UEs are considered tohave adequate service regardless of the levels of interference that maybe received from neighboring cells, so the interference metric for thereference cell is set to zero. In equation 4, this function isaccomplished by subtracting 5 from the number of users on the neighborcell. If there are five or fewer users then the first parameter of themax() function will be negative, resulting in a value of zero forM_((i)).

Equation 4 raises the ratio of active users on the neighbor cell toactive users on the reference cell to the third power. Thus, as theratio increases, the multiplier increases at a cubic rate. Such a cubicincrease provides improved performance of wireless multisite capacitycoordination algorithms compared to a linear increase.

In step 818, an interference impact metric I_(M(i)) is calculated foreach neighboring cell eNodeB_(C(i)) of the reference cell eNodeB_(R). Inan embodiment, the interference impact metrics are calculated bymultiplying the raw interference metric by the active user multipleaccording to the following equation 5:

I _(M(i)) =M *I _(raw(i))   [Equation 5]

For each reference cell, a value for I_(M(i)) may be calculated for eachof its neighbors. I_(M(i)) provides a measure of the impact ofinterference from eNodeB_(R) on the UEs served by eNodeB_(C(i)).

In step 820, the total interference impact metric, I_(MT), of eNodeB_(R)on all of its neighboring cells is calculated by summing together eachof the I_(M(i)) values as expressed in the following equation 6:

I _(MT)=Σ₁ ^(N)1_(M(i))   [Equation 6]

According to equation 6, the value of I_(MT) Is independent, of theresource utilization of the reference cell, eNodeB_(R). Variations inthe resource utilization of eNodeB_(R) are accounted for by the impactthat they have on the neighboring cell I_(MT) scores. In otherembodiments, other specific processes and policies may be used to arriveat a total interference impact metric that quantifies the interferenceimpact of a reference cell on its neighbors and increases as the impact,increases.

In step 822 a list, referred to herein as List_(neighbor) may be createdfor each reference cell eNodeB_(R). The list may include an identifierfor every cell that neighbors the eNodeB_(R), as well as the I_(MT)value for the eNodeB_(C(i)). The I_(MT) values may be added toList_(neighbor) after the I_(MT) values have been calculated for eachcell. The list may be stored on a non-transitory computer readablemedium. The lists may be compiled during the computation of interferencemetrics for a reference cell.

The following pseudocode is provided to help illustrate process 800 ofcalculating a total interference impact metric according to anembodiment, of the present invention:

FOR each eNodeB_(R)  FOR each neighbor eNodeB (eNodeB_(C(i)) where i = 1to N):    FOR each UE on eNodeB_(C(i)): Calculate UE interference metricfor eNodeB_(R):      Count the number of wireless resources,numResources, UE (e.g., number of      PRBs) assigned to eNodeB_(C(i))during the last measurement period      Calculate an exponent value fromthe RSSI measurements of the reference      eNodeB_(R) andeNodeB_(C(i)):       exp_value = (12.0 − (RSSIdB(eNodeB_(C(i))) -(RSSIdB(eNodeB_(R)) ) )/3.0      Calculate the UE Interference metric:      UE Interference metric = (numResources) * e^(exp)_value     ENDFOR   Calculate the raw interference metric by summing the UEinterference metric for each   UE for that eNodeB (I_(raw(i)))  Calculate the total number of active UEs, A_(N(i)) for eNodeB_(C(i))  Calculate the total of resources, R_(T(i)) utilized by eNodeB_(C(i))in the most recent   measurement period   Calculate the percentage ofresources, R_(util(i)), utilized by eNodeB_(C(i)) in the most recent  measurement period from R_(T(i)) and R_(MAX)   Calculate the activeuser multiple, M_(i), for this eNodeB_(R), eNodeB_(C(i)) pair  Calculate the interference impact metric for eNodeB_(C(i)): I_(M(i)) =M_(i) * I_(raw(i)).   Add eNodeB_(C(i)) to the List_(neighbor) for theeNodeB_(R)  END FOR Calculate the total interference impact metric,I_(MT), for eNodeB_(R) as the sum of the individual interference impactmetrics, I_(M(i)) END FOR

After a total interference impact, metric has been determined for eachcell, cell resources may be allocated to improve performance of acellular network. FIG. 10 illustrates an example of cell resourceallocation according to frequency. As seen in FIG. 10, power resourcesmay be adjusted in the frequency domain for a particular cell.

In the embodiment of FIG. 10, power is assigned to three levels: highpower (1.0), low power (0.5), and no power (0), and each frequency slot,is transmitted at one of those three levels for all time slots. In otherembodiments, the number of divisions may differ. The frequency slots inFIG. 10 represent one or more frequencies that may or may not becontiguous. An example of a frequency slot is a group of LTE PRBs,

Such variation is compatible with cellular networks using an orthogonalfrequency division multiplexing (OFDM) scheme. Each of the power levelsmay be a multiplier of a predetermined power such as the maximumtransmission power for a cell.

FIG. 11 illustrates an example of cell resource allocation according totime. In FIG. 11, high, low, and no power resources are assigned tovarious time slots regardless of frequency. Embodiments that allocateresources according to FIG. 11 are compatible with an OFDM scheme, aswell as a code division multiple access (CDMA) scheme.

FIG. 12 illustrates a process 1200 for determining a distribution ofpower resources for a reference cell eNodeB_(R). In an embodiment, aproportion of power resources for each cell in a cellular network isdetermined before assigning the resources to UE.

The power resources of each, cell are divided into sub-bands. A sub-bandis one or more block of resources in a frequency and/or time domain,such as one or more frequency and/or time slot. For example, in FIG. 10,one or more frequency slot F0-F7 may be a sub-band. In FIG. 11, asub-band may be one or more of time slots 1-8. In another embodiment, asub-band may be a combination of frequency and time slots, such asfrequency slot 10 and time slot 3.

The total number of sub-bands may be referred to as MAX_(subbands). Inan embodiment where the sub-bands correspond to time slots, a pattern ofsub-bands may repeat every max so that MAX_(subbands) corresponds to acycle. A default power setting for sub-bands may be high power. Theprocess 1200 is used to determine the number of low power sub-bands,L_(subbands), and the number of no power (empty) sub-bands,N_(subbands), for each reference eNodeB_(R).

In step 1202, a List_(neighbor) for a reference cell is sorted accordingto total interference impact metric values, hi other words, eacheNodeB_(C(i)) in a List_(neighbor) for a given reference cell eNodeB_(R)is arranged in order according to the I_(MT) value corresponding to theparticular eNodeB_(C(i)). In an embodiment, List_(neighbor) may bearranged in descending order of I_(MT) values.

In an embodiment, in step 1204, List_(neighbor) may be truncated so thatit only contains a predetermined number of entries. The neighboringcells with lower I_(MT) values are removed from consideration in theremaining steps of process 1200. Although embodiments of the presentinvention are not limited, to a particular value, in the followingdescription, the predetermined number of entries is live.

In step 1206, the fifth highest I_(MT) value is selected from the list.In an embodiment where the list is truncated to include at least fivevalues, the lowest score is the fifth highest score in the list, whichmay be referred to as the value 5thHighestScore. In an embodiment wherethere are less than five neighbors, then the 5thHighestScore value isset to zero.

In step 1208, a threshold value K is calculated. The value may becalculated by dividing the lowest I_(MT) value SthHighestScore by two.If K is less than a predetermined value, K may be set to thepredetermined value 1 mk. In an embodiment, I_(MIN) is 30,000, so ifhalf of 5thHighestScore is less than 30,000, K is set to 30,000.

The predetermined value I_(MIN) maybe different in other embodiments.Thus, in an embodiment, process 1208 a of calculating an I_(MIn) valuemay be performed. For example, I_(MIN) may be calculated according tothe following equation 7.

I_(MIN)=MAX_(subT)*MAX_(timeslots)*MIN_(interference)*MIN_(imbalance)*MIN_(neighbors)  [Equation 7]

in which MAX_(subT) is the maximum number of sub-band resourcesavailable to a cell during measurement period T, MAX_(timeslots) is themaximum number of timeslots during measurement period T,MIN_(interference) is a minimum interference multiplier, MIN_(imbalance)represents a minimum expected ratio between the highest and lowestI_(MT) values of neighboring cells on List_(neighbor), andMIN_(neighbors) represents a typical minimum number of neighboring cellsthat are serving UEs receiving interference from the reference celleNodeB_(R).

In an embodiment, MIN_(interference) may be 3, MIN_(imbalance) may be 2,and MIN_(neighbors) may be 2.5. In other embodiments, these values maybe adjusted according to existing and desired characteristics of thewireless network.

Step 1250 includes determining a total number of sub-bands that will beconfigured to transmit at power levels less than maximum power. Forexample, in an embodiment where there are three separate power levels ofhigh, low, and no power, step 1210 determines a number of sub-bands thatwill be assigned low power and no power. The total number of sub-bandsmay be referred to as SubbandCount, which, is derived according to thefollowing equation 8.

$\begin{matrix}{{SubbandCount} = {{FLOOR}*\left( {2.0*{\ln \left( \frac{I_{MT}}{K} \right)}} \right)}} & \left\lbrack {{Equation}\mspace{14mu} 8} \right\rbrack\end{matrix}$

in which the FLOOR, function returns an integer value. The SubbandCountvalue represents the number of sub-bands to be transmitted at powerlevels less than maximum power. In an embodiment, larger values of theratio of the I_(MT) for the reference cell and the neighbor cell withthe fifth highest I_(MT) results in a larger number of sub-bands of thereference cell being configured to transmit at low power and/or nopower.

In step 1212, power resources are assigned to sub-bands. In anembodiment with, three levels of sub-band power, low power sub-bands maybe represented as L_(subbands), and no power sub-bands maybe representedas N_(subbands). In an embodiment, sub-bands included in SubbandCountmay be initially configured as low power sub-bands until a number ofsub-bands are assigned in excess of a threshold value. In an embodiment,the threshold value is 37.5% of Max_(subbands), but embodiments of thepresent invention are not limited to that particular value. After thevalue of L_(subbands) exceeds the threshold value, additional sub-bandsare designated as no power subbands.

To help illustrate assigning power resources to sub-bands, an examplewill now be given of an execution of step 1212 in which SubbandCount issix. When the value of MAX_(subbands) is eight, all 8 sub-bands areinitially assigned high power. Sub-bands powers are then assigned withlow power until the number of sub-bands so assigned reaches a thresholdvalue. In this example, the threshold value of 37.5% is reached when lowpower is assigned to three sub-bands (⅜=37.5). Thus, low power isassigned to three sub-bands, and no power is assigned to a remainingnumber of sub-bands to be assigned, which in this example is the totalnumber of sub-bands (8) minus the difference between the value ofSubbandCount (6) and the number of L_(subbands) that have already beenestablished (3), which is three. Thus, in this example, high power isassigned to two sub-bands, low power is assigned to three sub-bands, andno power is assigned to the three remaining sub-bands.

In step 1214, a number of UE to assign to sub-bands is calculated. Inparticular, for wireless communications systems such as LTE, where UEsmust be pre-allocated to receive downlink data on high power or lowpower sub-bands, a number of UE which are allocated to low powersub-bands is determined before transmission. Step 1214 will be explainedin detail with respect to corresponding FIG. 13, which illustrates aprocess 1300 for determining the number of low and high power sub-bands.

In an embodiment, the UE attached to the reference cell that, have thehighest CINRs are allocated to the low power sub-bands. Low power UE maybe designated as UE_(LP). However, a UE should have a CINR in excess ofa threshold value to be allocated to low power resources. For example,in an embodiment, UE are only assigned to low power resources if theyhave a CINR value in excess of 10 dB, although embodiments of thepresent invention are not limited to this specific value.

Thus, in step 1302, a CINR value is compared to a threshold value. IT itis determined that no UE have a CINR value that exceeds the thresholdvalue, then high power resources are assigned to all UE and the processmay terminate.

In an embodiment using the LTE standard, the CINR value may be the CINRseen on reference signals. In an embodiment in a Universal MobileTelecommunications System (UMTS), the CINR value may be the CINR seen onthe common pilot channel Persons of skill in the art will recognize thatother CINR values may be used according to the parameters of thecellular network.

In an embodiment, the nominal number of UEs to be allocated to low powersub-bands is proportional to the ratio of the number of low powersub-bands to the sum of low power and high power sub-bands. Inparticular, in step 1304, the nominal number of UEs to be allocated tolow power sub-bands may be determined according to the followingequation 9.

$\begin{matrix}{{UE}_{LP} = {{FLOOR}\left( {A_{R}*Y*\frac{L_{subbands}}{{MAX}_{subbands} - N_{subbands}}} \right)}} & \left\lbrack {{Equation}\mspace{14mu} 9} \right\rbrack\end{matrix}$

in which Y is a multiplier which can be adjusted in various embodimentsin order to tune the number of UEs allocated to the low power sub-bands.In an embodiment, Y is 0.8.

In step 1306, a cheek is made to determine whether UE_(LP) is greaterthan zero. If the value does not exceed zero, then all low powersub-bands are allocated as no power sub-bands and the processterminates.

After calculating the number of low power sub-bands UE_(LP), step 1310may determine whether there are sufficient UE available with CINR abovethe threshold value in step 1302 to allocate to the low power sub-bands.If there are not enough suitable UEs to allocate to the low powersub-bands, then in step 1312 the number of low power sub-bands isdecremented, and the number of high power sub-bands is incremented.

In an embodiment, step 1314 may establish a threshold percentage ofno-power sub-bands, and not allow the number of no-power sub-bands toexceed the threshold value. If the number of no-power sub-bands exceedsthe threshold value, in step 1316 no-power sub-bands are reallocated tolow-power and high-power sub-bands until the number of no-powersub-bands is lower than the threshold value. In an embodiment, thethreshold value is 62.5%, although embodiments of the present inventionare not limited thereto.

Although processes 1200 and 1300 have been illustrated and described ina particular order, embodiments of the present invention are not limitedto the stated order. Furthermore, in some embodiments, not all of thesteps are performed.

The following pseudocode is provided to help illustrate an embodiment ofprocess 1200 of determining a distribution of power resources accordingto the present invention;

FOR each eNodeB (eNodeB_(R)): // Calculate the number of low power andno power subbands  Sort the cells in List_(neighbor) of eNodeB_(R) inorder of the total interference impact metric, I_(MT),  score of each ofneighbor cells (highest I_(MT) score first)  Truncate List_(neighbor) sothat it contains the six neighbor cells with the highest I_(MT) scores Select the 5^(th) highest I_(MT) score, 5thHighestScore, from the list;if there are fewer than 5  neighbors then 5thHighestScore is set to zero Calculate a threshold, K as follows:    K = (5thHighestScore)/2;    IfK < 30,000:     K = 30,000  Determine the total number of sub-bands thatwill be configured to transmit at low or no  power    If (I_(MT) > = K):    SubbandCount = FLOOR(2.0 * in(I_(MT) / K) )    else:    SubbandCount = 0;  Determine the number of low (L_(subbands)) and no(N_(subbands)) power sub-bands    switch (SubbandCount):     case 0:    case 1: N_(subbands) = 0; L_(subbands) = 0; break     case 2:N_(subbands) = 0; L_(subbands) = 2; break     case 3: N_(subbands) = 0;L_(subbands) = 3; break     case 4: N_(subbands) = 1; L_(subbands) = 3;break     case 5: N_(subbands) = 2; L_(subbands) = 3; break     default:N_(subbands) = 3; L_(subbands) = 3; break  If more than zero sub-bandsare to be configured to transmit at low power on this cell,  calculatethe number of UEs, UE_(LP), to assign to the low power sub-bands andupdate the  number of no/low power sub-bands if there are not enoughsuitable UEs to place in the  low power sub-bands  If (L_(subbands) >0):   LET UE_(CINR>10) = the number of UEs of that eNodeB with (CINR of10 dB or higher   While (1):    UE_(LP) = FLOOR( A_(R) * 0.8 *L_(subbands) / (MAX_(subbands) − N_(subbands)) );    If (UE_(LP) = = 0):    Nsubbands = Nsubbands + Lsubbands;     Lsubbands = 0;     break; //Breaks out of while statement    If ( (A_(R) > = 5) AND (UE_(CINR>10) >= UE_(LP)) ):     break; //Breaks out of while statement   N_(subbands)++; L_(subbands)−−;    If (N_(subbands) >MAX_(subbands) * 5/8):     N_(subbands) = MAX_(subbands) * 5/8;   Endwhile END FOR

After the number of low and no power sub-bands have been determined foreach cell, the actual assignment of low and no power sub-bands at eachcell takes place. Testing has demonstrated that random assignment oftransmit power to sub-bands may result in high levels of networkperformance. However, better results may be achieved through coordinatedallocation to alien sub-bands in frequency and/or time.

In an embodiment, as illustrated by FIG. 14, a process 1400 ofcoordinated allocation of power resources is performed. A process 1400of coordinated allocation of power resources may include a step 1402 ofranking cells by interference metric, a step 1404 of defining areference cell pattern, a step 1406 of defining a neighboring cellpattern, and a step 1408 of defining an array of positions.

The following pseudocode is provided to help illustrate an embodiment ofprocess 1300 of coordinated allocation of power resources according tothe present invention. The pseudocode assumes that sub-bands aredistributed in frequency, but persons of skill in the art will recognizethat it is readily adapted for embodiments where sub-bands aredistributed in time.

Record the I_(MT) score, N_(subbands), L_(subbands), and UE_(LP) foreach eNodeB. Rank each eNodeB_(R) by its I_(MT) score, LetPattern_(reference) = The pattern of high (H), low (L), and no (X) powersub-bands for eNodeB_(R) (e.g., H X L H H L L X). This pattern will beused by eNodeB_(R) for its transmissions. Scores are assigned to each ofthe subbands as follows:  High power sub-bands, H, are allocated a scoreof 0  Low power sub-bands, L, are allocated a score of 1  No powersub-bands, X, are allocated a score of 2 Pattern_(neighbors) is definedas the sum of the scores of the neighbor patterns allocated so far.  The neighbor pattern represents the collective power settings of theneighbor   eNodeBs of the reference eNodeB_(R).   e.g., Suppose thecurrent value of Pattern_(neighbors) is [2 0 1 3 0 1 2 0] and a new  neighbor is assigned Pattern [H X L H X H H L], then the new value of  Pattern_(neighbors) would be [2 0 1 3 0 1 2 0] + [0 2 1 0 2 0 0 1] =[2 2 2 3 2 1 2 1] An array, X-Positions is defined that specifies theorder in which no power sub-band positions are allocated:  X-Positions[] = {0, 4, 1, 5, 2, 6, 3, 7} An array, L-Positions is defined thatspecifies the order in which low power sub-band positions are allocated: L-Positions[ ] = {7, 3, 6, 2, 5, 1, 4, 0} For each reference eNodeB_(R)(in order of I_(MT) score starting with the eNodeB_(R) with the highestI_(MT) score):  IF ( (N_(subbands) > 0) ∥ ( (L_(subbands) > 0) )  Subbands = [0 0 0 0 0 0 0 0]   Pattern_(reference) = [0 0 0 0 0 0 0 0]  FOR each element of the List_(neighbor):    Subbands = Subbands +Pattern_(neighbors)   END FOR   // Determine which subbands shall beconfigured to transmit with no power   FOR (j = 0; j < N_(subbands); j ++):    position_index = 0xff // undefined position    FOR (i = 0; i <MAX_(subbands); i + +):     If (Pattern[(X-Positions[i])] = = 0):     if(position_index = = 0xff):      position_index = i;     elseif(Subbands[ X-Positions[i] ] <      Subbands[ X-Positions[position_index]] ):      position_index = i;    Pattern[X-Positions[position_index]] =2; // this is the value of a No power    resource (X)   Subbands[X-Positions[position_index]] + = 2; // this is the value ofa No power    resource (X)   // Determine which subbands shall beconfigured to transmit with low power   FOR (j = 0; j < L_(subbands);j + +):    position_index = 0xff // undefined position    FOR (i = 0; i< MAX_(subbands); i + +):     If (Pattern[(L-Positions[i])] = = 0):     if (position_index = = 0xff):       position_index = i;      elseif(Subbands[L-Positions[i]] < (Subbands[L-Positions[position_index]]):      position_index = i;    Pattern[L-Positions[position_index]] = 1;// this is the value of a Low power    resource (L)   Subbands[L-Positions[position_index]] + = 1; // this is the value ofa No power    resource (X)   // Update neighbor patterns   FOR eachelement of the List_(neighbor):    Pattern_(neighbors) + =Pattern_(reference)   END FOR  END IF END FOR

Embodiments of the present invention may implement processes forwireless multisite capacity coordination. In some embodiments, aspectsof the present invention, such as the values of certain variables, canbe varied by time of day or based on the subsection of the network inwhich the wireless multisite capacity coordination is applied.

While several embodiments of the present invention have been illustratedand described herein, many changes can be made without departing fromthe spirit and scope of the invention. Accordingly, the scope of theinvention is not limited by any disclosed embodiment. Instead, the scopeof the invention should be determined from the appended claims thatfollow.

What is claimed is:
 1. A system for improving the performance of awireless communication: network, the system comprising: a processor; anda non-transitory computer readable medium with computer executableinstructions stored thereon which, when executed by the processor,perform the following method: calculating a total interference impactmetric for a reference cell; determining a distribution of powerresources for the reference cell and a plurality of neighboring cells;and allocating the power resources to sub-bands for the reference celland the plurality of neighboring cells,
 2. The system of claim 1,wherein the non-transitory computer readable medium with computerexecutable instructions stored thereon further includes instructionswhich, when executed by the processor, cause the processor to performthe following steps: determining a number of resources assigned to thereference cell within time-period T; and calculating user equipment (UE)Interference metrics for each UE attached to each of a plurality ofneighboring cells, each of the neighboring cells having attached UEwhich experiences interference from the reference cell.
 3. The system ofclaim 2, wherein calculating the total interference impact metric forthe reference cell comprises: calculating raw interference metrics foreach neighboring cell; determining a total number of active UEs for eachneighboring cell; calculating a total amount of resources used by eachneighboring cell during the time period T; calculating a percentage ofresources used by each neighboring cell during the time period T;calculating an active user multiple for each neighboring cell;multiplying the raw interference metrics for each neighboring cell bythe active user multiple for each neighboring cell to determineIndividual Interference impact metrics; and summing the individualinterference impact metrics.
 4. The system of claim 2, whereincalculating the UE interference metrics further comprises; counting anumber of resources assigned to each neighboring cell, during the timeperiod T; calculating an exponent value from RSSI measurements of thereference cell and each neighboring cell; and calculating UEinterference metrics based on the exponent value.
 5. The system of claim4, wherein calculating an exponent value from RSSI measurements isconducted according to the following equation:${exp\_ value} = \frac{12.0 - \left( {{{RSSIdB}\left( {eNodeB}_{c{(i)}} \right)} - {{RSSIdB}\left( {eNodeB}_{R} \right)}} \right.}{3.0}$in which RSSIdB(eNodeB_(c(i)) represents received signal strengthinformation (RSSI) values received at a UE from the neighboring cell towhich the UE is attached, and RSSIdB(eNodeB_(R)) represents an RSSIvalue received at a UE from the reference cell.
 6. The system of claim4, wherein calculating the UE interference metrics based on the exponentvalue is conducted according to the following equation:UE Interference Metric=(numResources)*e^(exp) _(—) _(value) in whichnumResources is a number of physical resources used by the UE during thetime period T.
 7. The system of claim 3, wherein the percentage ofresources R_(Util(i)) used by the i′th neighboring cell is calculatedaccording to the following equation:$R_{{Util}{(i)}} = \frac{R_{T{(i)}}}{R_{Max}}$ in which R_(T(i)) is atotal number of wireless resources allocated to all UEs attached to theneighboring cell i during measurement period T, and R_(max) is a maximumnumber of wireless resources than can be allocated to UEs by neighboringcell i during the time period T.
 8. The system of claim 3, wherein thenon-transitory computer readable medium with computer executableinstructions stored thereon further includes instructions which, whenexecuted by the processor, cause the processor to perform the followingsteps: after calculating the interference impact metric, adding eachneighboring cell to a list of neighbor cells for the reference cell; andusing the list of neighbor cells to determine the distribution of powerresources.
 9. The system of claim 3, wherein, calculating an active usermultiple M$ for each neighboring cell is conducted according to thefollowing equation:$M_{(i)} = {\max \left( {\left( {R_{{Util}{(i)}}*\frac{A_{N{(i)}} - x}{A_{R} + 1}} \right)^{3},0} \right)}$in which R_(Util(i)) is the airlink utilization percentage ofneighboring cell i, A_(N(i)) is a number of UE attached to theneighboring cells, A_(R) is a number of active UE attached to thereference cell, and x is a number of active UE which are attached toneighboring cell i.
 10. The system of claim 1, wherein calculating atotal interference impact metric for the reference cell includescalculating an interference impact metric for each neighbor cell andmultiplying the interference impact metrics by an active user multiple,and the active user multiple M(u for each neighboring cell is conductedaccording to the following equation:$M_{(i)} = {\max \left( {\left( {R_{{Util}{(i)}}*\frac{A_{N{(i)}} - x}{A_{R} + 1}} \right)^{3},0} \right)}$in which R_(Util(i)) the airlink utilization percentage of neighboringcell i, A_(N(i)) is a number of UE attached to the neighboring cells,and A_(R) is a number of active UE attached to the reference cell, and xis a number of active UE which are attached to neighboring cell i.
 11. Amethod for improving the performance of a wireless communicationnetwork, comprising: calculating a total interference impact metric fora reference cell; determining a distribution of power resources for thereference cell and a plurality of neighboring cells; allocating thepower resources to sub-bands for the reference cell and the plurality ofneighboring cells; and determining the number of UEs to assign to eachsub-band of the reference cell and the plurality of neighboring cells.12. The system of claim 11, farther comprising: determining-a number ofresources assigned to the reference cell within time period T; andcalculating user equipment (UE) interference metrics for each UEattached to each of a plurality of neighboring cells, each of theneighboring cells having attached UE which experiences interference fromthe reference cell.
 13. The method of claim 12, wherein calculating thetotal interference impact metric for the reference cell comprises:calculating raw interference metrics for each neighboring cell;determining a total number of active UEs for each neighboring cell;calculating a total amount of resources used by each neighboring cellduring the time period T; calculating a percentage of resources used byeach neighboring cell during the time period T; calculating an activeuser multiple for each neighboring cell; multiplying the rawinterference metrics for each neighboring cell by the active usermultiple for each neighboring cell to determine individual interferenceimpact metrics; and summing the individual interference impact metrics.14. The method of claim 13, wherein calculating an active user multipleM_((i)) for each neighboring cell is conducted according to thefollowing equation:$M_{(i)} = {\max \left( {\left( {R_{{Util}{(i)}}*\frac{A_{N{(i)}} - x}{A_{R} + 1}} \right)^{3},0} \right)}$in which R_(Util(i)) the airlink utilization percentage of neighboringcell i, A_(N(i)) is a number of UE attached to the neighboring cells,and A_(R) is a number of active UE attached, to the reference cell, andx is a number of active UE which are attached to neighboring cell i. 15.The method of claim 13, wherein calculating the UE interference metricsfurther comprises: counting a number of resources assigned to eachneighboring cell during the time period T; calculating an exponent valuefrom RSSI measurements of the reference cell and each neighboring cell;and calculating UE interference metrics based on the exponent value. 16.The method of claim 15, wherein calculating an exponent value from RSSImeasurements is conducted according to the following equation:${exp\_ value} = \frac{12.0 - \left( {{{RSSIdB}\left( {eNodeB}_{c{(i)}} \right)} - {{RSSIdB}\left( {eNodeB}_{R} \right)}} \right.}{3.0}$in which RSSIdB(eNodeB_(c(i)) represents received signal strengthinformation (RSSI) values received at a UE from the neighboring cell towhich the UE is attached, and RSSIdB(eNodeB_(R)) represents an RSSIvalue received at a UE from the reference cell, and wherein calculatingthe UE interference metrics based on the exponent value is conductedaccording to the following equation:UE Interference Metric=(numResources)*e^(exp) _(—) _(value) in whichnumResources is a number of physical resources used by the UE during thetime period T.
 17. The method of claim 13, wherein the percentage ofresources R_(Util(i)) used by the i′th neighboring cell is calculatedaccording to the following equation:$R_{{Util}{(i)}} = \frac{R_{T{(i)}}}{R_{Max}}$ in which R_(T(i)) is atotal number of wireless resources allocated to all UEs attached to theneighboring cell i during measurement period T, and R_(max) is a maximumnumber of wireless resources than can be allocated to UEs by neighboringcell during the time period T.
 18. A non-transitory computer readablemedium with computer executable instructions stored thereon which, whenexecuted by the processor, perform the following method: calculating atotal interference impact metric for a reference cell; determining adistribution of power resources for the reference cell and a pluralityof neighboring cells; allocating the power resources to sub-bands forthe reference cell and the plurality of neighboring cells; anddetermining the number of UEs to assign to each sub-band of thereference cell and the plurality of neighboring cells.
 19. Thenon-transitory computer readable medium of claim 18, further comprisingcomputer executable instructions stored thereon which, when executed bythe processor, perform the following method: determining a number ofresources assigned to the reference cell within time period T; andcalculating user equipment (UE) interference metrics for each UEattached to each of a plurality of neighboring cells, each of theneighboring cells having attached UE which experiences interference fromthe reference cell.
 20. The computer readable medium of claim 18,wherein calculating the total interference impact metric for thereference cell comprises: calculating raw interference metrics for eachneighboring cell; determining a total number of active UEs for eachneighboring cell; calculating a total amount of resources used by eachneighboring cell during the time period T; calculating a percentage ofresources used by each neighboring cell during the time period T;calculating an active user multiple for each neighboring cell;multiplying the raw interference metrics for each neighboring cell bythe active user multiple for each neighboring cell to determineindividual impact metrics; and summing the individual impact metrics.21. The computer readable medium of claim 20, wherein calculating anactive user multiple for each neighboring cell is conducted according tothe following equation:$M_{(i)} = {\max \left( {\left( {R_{{Util}{(i)}}*\frac{A_{N{(i)}} - x}{A_{R} + 1}} \right)^{3},0} \right)}$in which R_(util(i)) is the airlink utilization percentage ofneighboring cell i, A_(N(i)) is a number of UE attached to theneighboring cells, and A_(R) is a number of active UE attached to thereference cell, and x is a number of active UE which are attached toneighboring cell i.
 22. The computer readable medium of claim 19,wherein calculating the UE interference metrics further comprises:counting a number of resources assigned to each neighboring cell duringthe time period T; calculating an exponent value from RSSI measurementsof the reference cell and each neighboring cell; and calculating UEinterference metrics based, on the exponent value.
 23. The computerreadable medium of claim 20, wherein calculating an exponent value fromRSSI measurements is conducted according to the following equation;${exp\_ value} = \frac{12.0 - \left( {{{RSSIdB}\left( {eNodeB}_{c{(i)}} \right)} - {{RSSIdB}\left( {eNodeB}_{R} \right)}} \right.}{3.0}$in which RSSIdB(eNodeB_(c(i)) represents received signal strengthinformation (RSSI) values received at a UE from the neighboring cell towhich the UE is attached, and RSSIdB(eNodeB_(R)) represents an RSSIvalue received at a UE from the reference cell, and wherein calculatingthe UE interference metrics based on the exponent value is conductedaccording to the following equation: UE InterferenceMetric=(numResources)*e^(exp) _(—) _(value) in which numResources is anumber of physical resources used by the UE during the time period T.